On the subject of the British not intercepting Bonaparte as he sailed from Egypt to France or perhaps even deliberately allowing him to pass by, Elizabeth Sparrow has some interesting things to say in her book Secret Service: British Agents in France. I don't have it on hand at the moment but from memory she presents some evidence suggesting that Sidney Smith may have deliberately allowed Bonaparte to sail unhindered, due to reasons of (misguided) British policy. Perhaps someone has access to this unfortunately rather rare work and can shed further light on the matter?

Regards,
Chris